Traditional methods for processing photosensitive film contained in cartridges typically involves the separation of the filmstrip from the cartridge prior to processing. In one method, the photographic film is cut away from the cartridge, and taped to a leader board or a length of flexible film, after which the film is drawn through a series of tanks containing the required processing solutions. This method has satisfied the reliability and efficiency requirements for the traditional photofinishing systems, largely due to the fact that the film cartridge is discarded and thus no longer serves any other purposes in subsequent stages of image preparation, storage and retrieval.
Recent advances in film cartridges, such as described in U.S. Pat. No. 4,834,306, disclose a photographic film cartridge wherein the filmstrip may be thrust out of the cartridge, and retracted back into the cartridge a number of times (hereinafter referred to as thrust film cartridge). For example, the thrust film cartridge can be used as a primary storage for the processed film, and can be used with related film handling equipment which can be configured to accept the thrust-type film cartridge. The ability to execute other tasks involved in the preparation, storage and retrieval of images from a specific filmstrip cartridge is advantageous to the photographer and to the photofinisher. In particular, the method of identifying, sorting, and preferentially reproducing (e.g., selecting desired print parameters; such as frame number, size, quantity, setup, and balancing data) images may be significantly enhanced. It has been proposed that the thrusting filmstrip be detached from the thrust film cartridge prior to chemical processing and processed in the traditional photofinishing equipment and then reattached to the original film cartridge (or similar cartridge) for storage.
The detached method exhibits a number of inherent disadvantages. Specifically, the correct filmstrip and cartridge must be reunited; detaching and reattaching the filmstrip can result in damage to the leader and/or trailing edge of the film which then must be cut and reshaped which adds cost to the process; reattaching of the film can be difficult and require certain standardized equipment. Additionally, the detached system cannot take advantage of the fact that only partial portions of the film may be exposed and developed without exposing the remaining portion of the film in the cartridge.
U.S. Pat. No. 5,093,686 discloses the processing of photosensitive material while the filmstrip is still connected to the film cartridge. This is accomplished by thrusting the film out of the cartridge and dipping the filmstrip into successive tanks, typically referred to as the dip and dunk process. The device includes a vertical transport mechanism for lifting the film up to a horizontal transport position where the film can then be moved horizontally while the film is still extended from the cartridge. This type of process results in the images at the bottom end of the strip to experience more development time than the portions above. Additionally, further expensive equipment is required to move and transport the film through the system.
One solution to the foregoing problem is disclosed in U.S. Pat. No. 5,543,882, filed Oct. 27, 1994, by Daniel M. Pagano, Richard B. Wheeler, and Kevin J. Klees, entitled "Method and Apparatus for Processing Photosensitive Film", which is hereby incorporated by reference. This prior invention teaches the use of a propeller immersed in the developing fluid to transport the fluid past the film which is contained in a spiral reel.
This processing technique has proven to provide excellent development uniformity, and will also reduce the development time required. However, both of these desirable effects require high agitation. This is accomplished by turning the propeller at higher speeds. This introduces a new problem by drawing air from the upper surface of the fluid into the flowstream produced by the propeller. This is disadvantageous since it can speed up the oxidation of the developer fluid. Oxidation of the developer reduces its effectiveness and can require more replenishment or more frequent replacement of the developer. An additional deleterious effect is the production of large volumes of foam on the surface of the fluid.
The present invention provides an apparatus for reducing the amount of air drawn into a photographic processing fluid by a high agitation processor. The present invention reduces these troublesome effects by separating the processing tank into an upper and lower segment by the use of a baffle. This horizontal baffle placed above the film holding spiral confines the turbulence of the agitation to the lower section of the tank. The fluid above the baffle is largely undisturbed by the violent agitation below.